This invention concerns a plug system for closing cell vents in a storage battery and a battery cap for use in the plug system.
Storage batteries consist of two chemically different electrodes that are arranged in a case with a cap in a mostly fluid or concentrated electrolyte. In the lead batteries generally used in motor vehicles, the electrodes are made of lead and are designed to be grid-shaped. The grid mesh are filled with lead dioxide PbO2 on the positive side and with so-called spongy lead, finely dispersed porous lead, on the negative side. Sulfuric acid H2SO4 is generally used as the electrolyte. In lead batteries, especially for motor vehicles, several cells are connected in a row. One side of the first cell and one side of the last cell has a contact pole that projects through the cap on the case. During the charging processes, chemical reactions take place that cause gas to be formed. Most storage batteries have gas outlet vents in their caps.
To prevent and reduce electrolyte evaporation, on one hand, and to be able to send the gases formed when the storage battery is overcharged outside into the air surrounding the battery before a critical excess pressure is reached inside the cells, the individual cells of a storage battery are generally closed by means of plugs designed as excess pressure valves. To prevent the batteries from exploding, two basic ways of degassing are known for removing the easily combustible gases created. One is to let off the gas directly via plugs that cap the individual cell vents, another is via a central gas line in which the individual cell vents are connected to one another via a transverse bore hole in the cap of the storage battery case. In the last degassing variation, the cell vents in the battery case above the channel made by the transverse vent are capped, are gas-tight and generally come out in the front of the case. In both ways of removing gas, the gases pass through a porous filter disk, a so-called frit, before leaving the battery, especially to prevent backfires inside the battery and the damage associated with them.
This invention is based on the problem of providing a plug system for capping the cell vents of a storage battery that consists of the fewest possible simple elements, with a combination of individual elements that can be adjusted to different battery designs, that can be adapted to meet the needs of individual batteries and that meet the requirements set for the main degassing variations, especially in terms of backfire protection and sealing. The plug system in the invention should also be very economical in terms of production, assembly and storage.
To solve this problem, this invention has proposed a plug system for capping the cell vents of a storage battery that consists of a plug body that can be used in a cell vent which holds a valve element and a plug, providing a normally closed, fluidic connection between the inside of the cells and the atmosphere surrounding the storage battery.
The plug system in the invention thus basically consists of three simple basic elements that bring with them low production, assembly and storage costs and a low expense in providing the corresponding technical manufacturing equipment and have no problem meeting the requirements for various storage battery designs and degassing variations.
In one advantageous embodiment of the invention, the plug body has at least one section that is reduced compared to the outer diameter of the plug body. This makes a basically annular projection on one end of the generating surface of the plug body which provides a basically annular stop surface lying on the outer front surface surrounding the cell vent of the storage battery cap and makes possible, for example, simple, precise insertion of the plug body into the cell vent. Advantageously, the storage battery cap has a negatively formed receptacle corresponding to the annular projection of the plug body which provides at least one front surface corresponding to the annular stop surface formed by the projection. The basically annular projection of the plug body can be used to attach the plug body in the cell vent. For this, the projection can have an attachment element on the outside, for example, or in the area of the projection in the cell vent that is glued, soldered or otherwise connected to the cap. Advantageously, the plug body can be inserted tightly, especially gas-tight in the cell vent. For this, the plug body has at least one sealing element, preferably an O-ring. According to one particularly advantageous embodiment of the invention, the sealing element is molded on the plug body and is, for example, a sealing ring injection-molded onto the plug body, and it can then be produced in a two-component process. Advantageously, the sealing element is arranged in an area of the plug body next to the annular projection. This guarantees that the plug body can be inserted safely into the cell vent and is gas-tight. Likewise, the annular projection of the plug body can have an area that at least partially holds the sealing element. Moreover, the projection can be designed to be conical, so that there is a guide when the plug body is inserted into the cell vent that can prevent it from being inserted incorrectly.
In another especially advantageous embodiment of the invention, the plug body has at least one section in the middle that is reduced compared to the outer diameter of the plug body, with at least one vent. Advantageously, the sections that are enlarged compared to the middle of the plug body are designed to be annular, so that a space is formed when the plug body is inserted between the middle, reduced section of the plug body and the battery case cap that provides a fluidic connection to the inside of the cells through at least one vent in the reduced section. Advantageously, the space formed by the reduced section in the middle part of the plug body and the battery case cap when the plug body is inserted is gas-tight. Advantageously, the sections connected to the reduced section in the middle of the plug body have a sealing element, preferably a molded O-ring.
In another advantageous embodiment of the invention, the plug body has an attachment element on the end facing the inside of the cells, with which the plug body can be attached in the cap. For this, the plug body has, for example, at least one projection that grasps behind the cap on the end. With the projection, the plug body is fixed when inserted in the cap and can no longer be removed from it. Advantageously, the plug body is held fast when inserted by pressing it into the cap. In this way, the plug body is securely attached, for one thing, and, for another, the most gas-tight insertion is made possible. In another especially advantageous embodiment of the invention, the plug body has a thread on at least one of the sections of the plug body next to the reduced section that matches a corresponding thread provided in the cap.
According to another advantageous embodiment of the invention, the plug body has a section inside to hold the valve element. In this way, the valve element can be placed in the plug body extremely simply with no problem. Advantageously, the section for holding the valve element is next to at least one vent in the generating surface of the plug body, so that the valve element normally caps the fluidic connection between the space formed by the reduced section of the plug body and the cap and the inside of the cell. Moreover, the vent in the generating surface of the plug body cannot be capped accidentally by the valve element. Advantageously, the section for the valve element forms a step on which the valve element can be mounted. In another advantageous embodiment of the invention, the generating surface of the section holding the valve element is designed to be slightly conical, so that the valve element can be fixed in the plug body by slight press-fitting. Likewise, it is possible for the valve element to have slightly conical outer walls, which make slight press-fitting possible in the area of the section provided for holding it inside the plug body. In another advantageous embodiment of the invention, the plug body in the area of the section has at least one projection for fixing the valve element in that area. Preferably, this projection is designed to be annular.
In another advantageous embodiment of the invention, the plug body has at least one intermediate wall inside forming a baffle plate which is preferably in a section next to the valve element toward the inside of the cells. The intermediate wall forming a baffle plate forces gas flowing from inside the cells to change direction and holds back the entrained fluid to protect the sealing element, for example, a rubber membrane on the valve element. The gas flowing out can then precipitate on the intermediate wall, and thus particles of fluid can condense on the wall and flow back inside the cells.
According to another advantageous embodiment of the invention, the plug has a vent. This creates the possibility of degassing through the cell cap. Advantageously, the vent is arranged in the middle of the plug.
In another advantageous embodiment of the invention, the plug can be snapped into the plug body. This guarantees that the plug, especially in the area near the cell vent, closes flush with the plug body. Advantageously, the plug can be inserted tightly into the plug body. This guarantees that a fluidic connection can be made only by the vents provided for it. Advantageously, the plug can be attached in the plug body. For this, the plug can be attached, for one thing, with an attachment element, for example with a thread corresponding to the plug body or by gluing, welding, for example ultrasonic welding, or the like. The plug is fixed in the plug body by means of press fitting in an advantageous way. This seals the plug in the plug body and makes attachment extremely simple.
According to another especially advantageous embodiment of the invention, the plug has a section inside to hold a filter disk. Advantageously, the plug has at least one projection to attach the filter disk in the receptacle provided for it, which is preferably designed to be annular and holds the back of the filter disk when in use.
In another especially advantageous embodiment of the invention, the vent in the generating surface of the plug body can be inserted in the plug body to close it. With only one plug body, this allows both central degassing through a transverse channel provided in the storage battery cap and degassing through the respective cell cap.
In another advantageous embodiment of the invention, with a plug with an eccentric vent and a plug body with a reduced central section with vent, both central degassing and degassing through the cell cap, hence the plugs, can be achieved by different positions for inserting the plug into the plug body. Thus, in the first position, for example, the vent in the surface of the plug body is capped by the plug and in the second position, the vent in the plug is capped by the plug body.
Advantageously, the valve element used in the plug body is an excess-pressure valve, so that a normally closed valve is provided that only opens when there is a certain pressure inside the cell. Advantageously, the valve vent is proportional to the excess pressure inside the cell.
Moreover, with this invention, a storage battery cap is proposed for use in the plug system in the invention that is characterized, for backfire-safe degassing, by an insert that can be used in the storage battery cap and provides a fluidic connection between the inside of the cell and the atmosphere surrounding the storage battery that allows degassing in front. Advantageously, the insert forms a tunnel-shaped channel and has at least one receptacle for a filter element. The filter disk can retain particles of fluid in the gas and, due to the design of the channel, which advantageously runs basically perpendicular to a central degassing channel in the battery cap, the gas flow is subjected to changes in direction. Due to the funnel-shaped route, the space for the gas in the direction of the degassing vent keeps being reduced, so that the gas flowing out and precipitating on the walls of the funnel can further condense and flow back inside the cells.
According to another advantageous embodiment of the invention, the filter element can be arranged directly next to the space formed by a plug body and the storage battery cap, so that flames from backfires cannot get inside the storage battery. Advantageously, the filter disk of the insert is the same size as the filter disk in the plug system.
According to another advantageous embodiment of the invention, the insert can be used as a seal in the storage battery cap. For this, it can be snapped, glued, welded, screwed or otherwise attached, for example, in the storage battery cap.
According to another especially advantageous embodiment of the invention, the plug system in the invention is used for the insert. For one thing, this further increases the possibilities of using the plug system, and, for another, it also makes front degassing possible with the same plug system and with a small number of components, in addition to capping the cell vents of a storage battery.
According to another particularly advantageous embodiment of the invention, the storage battery cap in the area near the cell vents has cam-like projections that make it possible to seal the cell vents axially. This design for the cell vents of the storage battery cap can provide a safe seal both radially and axially using a plug body that has with sealing elements. This further enhances the seal on the storage battery. The design for the cell vents of a storage battery cap with cam-like projections can also be used advantageously without the plug system in the invention and made with other battery caps or inserts.
Other advantages and features of the invention will be explained in greater detail using the examples of embodiment shown in the figures.